Abstracto

MOLECULAR IDENTIFICATION OF ROTYLENCHULUS RENIFORMIS (NEMATODA) BY USING ITS REGION OF RDNA

Swetha sudha N, Ravindar G, Nagaraja Rao P and Geeta Rajalingam

Background: Reniform nematode (Rotylenchulus reniformis) is widely distributed in all cotton (Gossypium spp.) grown regions of India. In Reniform nemotode infection, the growth of cotton roots and shoots was reduced at level of more than 8 and 1 nematode per g soil, respectively. DNA-based Molecular identi?cation of Plant parasitic nematode species has been determined by Internal Transcribed spacer (ITS) gene with PCR Techniques. The ribosomal DNA (rDNA) is a novel genetic marker and it is a multi-gene family consisting of many copies (100-500 in animals) of genes encoding for three ribosomal components 28S, 5.8S and 18S. Phylogeny is the history of organism lineage as they change through time. It implies that different species arise from previous forms via decent and that all organisms from the smallest microbes to the largest plants and vertebrates were connected by the passage by genes along the branches of the phylogenetic tree that links all the life form. In this study we have evaluated the diagnostic utility of the ITS1 and ITS2 region for constructing phylogenetic trees and determining taxonomic identity of Plant parasitic nematode species. Results: Rotylenchulus reniformis was collected from soil and root samples of Cotton crop and from Rotylenchulus reniformis (PPN) the ITS region of rDNA sequence is isolated. Phylogenetic analyses of Neighbor Joining (NJ) was distance based method, in this our sequence Rotylenchulus reniformis and Rotylenchulus reniformis of USA country were formed as one clade. Rotylenchulus reniformis of ITS gene sequence depicting high congruence with Rotylenchulus reniformis of USA country by 100 bootstrap replicate values. Conclusions: The ITS region becomes an important taxonomic feature in nematode identification. ITS versatility, specificity, effort of experimental manipulation, and growing ITS databases should accelerate its application in nematology. Most interesting finding in our studies with reference to plant parasitic nematode and its host plant suggested that ITS gene sequence helps in identifying nematode pest status and host plant susceptibility. Thus, these studies will help us to develop the Integrated Pest Management (IPM) package for a specific host plant and its variety. At the same time ITS supports Quarantine technology with reference to agro product export and import.